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Ground improvement in transport geotechnics - from theory to practice

Conference Paper


Abstract


  • In order to meet the ever-increasing demand for public and freight mobility, concerted efforts are

    needed to improve transport efficiency, and ensure the maintenance cost of highways and railways to sustainable

    levels. Ballast and subgrade are major components of rail track infrastructure, and understanding their integrated

    behaviour as layered strata is of utmost importance. In order to investigate their performance, sophisticated

    numerical modeling techniques using the Discrete Element Method (DEM) and Finite Element Method (FEM)

    are commonly employed, but the micro-mechanics of particulate interactions are often taken for granted rather

    than studied in depth. The salient aspects of particle degradation and confining pressure are discussed through

    the use of advanced elasto-plastic constitutive models. Applications of DEM to study the behavior of coal-fouled

    ballast subjected to cyclic loading using a track process simulation apparatus are also presented. The DEM

    enabled the discrete nature of ballast aggregates to be modeled considering their realistic size and shape, as well

    as through the force chains developed at contacts.A radial consolidation model under cyclic loading is proposed

    to capture the behavior of soft clays subjected to cyclic loadingwhen radial drainage is allowed during the loading

    period. The effects of the cyclic stress history on the generation of excess pore pressure are considered in the

    proposed model. This model is verified against the results of large-scale triaxial tests. In addition, the study of

    the behavior of artificially compacted subgrade, is vital to avoid unwanted volume changes caused by moisture

    variation that can contribute to poor track performance. A model is proposed for assessing the performance

    of compacted subgrades by evaluating the small strain behavior, considering the soil matric suction, the water

    content and the compaction energy level. This paper discusses the stability of the transport infrastructure at small

    and large strains based on numerical methods supported through advanced constitutive algorithms and validated

    against large-scale laboratory data.

Publication Date


  • 2015

Citation


  • Indraratna, B., Nimbalkar, S., Rujikiatkamjorn, C. & Heitor, A. (2015). Ground improvement in transport geotechnics - from theory to practice. In F. Oka, A. Murakami, R. Uzuoka & S. Kimoto (Eds.), Computer Methods and Recent Advances in Geomechanics (pp. 35-44). United Kingdom: Taylor & Francis.

Scopus Eid


  • 2-s2.0-84907303187

Ro Metadata Url


  • http://ro.uow.edu.au/eispapers/2929

Start Page


  • 35

End Page


  • 44

Place Of Publication


  • United Kingdom

Abstract


  • In order to meet the ever-increasing demand for public and freight mobility, concerted efforts are

    needed to improve transport efficiency, and ensure the maintenance cost of highways and railways to sustainable

    levels. Ballast and subgrade are major components of rail track infrastructure, and understanding their integrated

    behaviour as layered strata is of utmost importance. In order to investigate their performance, sophisticated

    numerical modeling techniques using the Discrete Element Method (DEM) and Finite Element Method (FEM)

    are commonly employed, but the micro-mechanics of particulate interactions are often taken for granted rather

    than studied in depth. The salient aspects of particle degradation and confining pressure are discussed through

    the use of advanced elasto-plastic constitutive models. Applications of DEM to study the behavior of coal-fouled

    ballast subjected to cyclic loading using a track process simulation apparatus are also presented. The DEM

    enabled the discrete nature of ballast aggregates to be modeled considering their realistic size and shape, as well

    as through the force chains developed at contacts.A radial consolidation model under cyclic loading is proposed

    to capture the behavior of soft clays subjected to cyclic loadingwhen radial drainage is allowed during the loading

    period. The effects of the cyclic stress history on the generation of excess pore pressure are considered in the

    proposed model. This model is verified against the results of large-scale triaxial tests. In addition, the study of

    the behavior of artificially compacted subgrade, is vital to avoid unwanted volume changes caused by moisture

    variation that can contribute to poor track performance. A model is proposed for assessing the performance

    of compacted subgrades by evaluating the small strain behavior, considering the soil matric suction, the water

    content and the compaction energy level. This paper discusses the stability of the transport infrastructure at small

    and large strains based on numerical methods supported through advanced constitutive algorithms and validated

    against large-scale laboratory data.

Publication Date


  • 2015

Citation


  • Indraratna, B., Nimbalkar, S., Rujikiatkamjorn, C. & Heitor, A. (2015). Ground improvement in transport geotechnics - from theory to practice. In F. Oka, A. Murakami, R. Uzuoka & S. Kimoto (Eds.), Computer Methods and Recent Advances in Geomechanics (pp. 35-44). United Kingdom: Taylor & Francis.

Scopus Eid


  • 2-s2.0-84907303187

Ro Metadata Url


  • http://ro.uow.edu.au/eispapers/2929

Start Page


  • 35

End Page


  • 44

Place Of Publication


  • United Kingdom